Control for internal-combustion engines



Ml 18 1950 K. v. ANDERSON coN'rRoL Foa INTERNAL-couusfrzom msms `FiledSept. 18, 1946 Snvcntor Karl V. Anderson Gttorucgs aliased apr. is, 195o2,504,243 CONTROL FOR INTERNAL-COMBUSTION ENGINES Karl V. Anderson,Milwaukee, Wis., assigner to Nordberg Manufacturing Company. Milwaukee.Wis., a corporation of Wbconsin Application September 18, 1946, SerialNo. 897,773

7 Claims. (Cl. 12S- 1) This invention relates to two cycle internalcombustion engines of the type in which fuel (either gaseous or liquid)is injected. and combustion air is delivered under pressure by a bloweror the like. The air so delivered may or may not eiTect supercharging.

Engines oi this type operate erratically at part load, particularly whenthe quantity of fuel is controlled by a governor. Below :V4 load themixture tends to be unduly weak and burn erratically. If combustion isweak (even though the quantity of fuel be correct) the governor willrespond and increase fuel. The engine speed rises and the governor cutsdown the fuel causing a repetition of the weak combustion. Thus theengine speed is irregular and the performance of the engineunsatisfactory.

The present invention is based on the discovery by applicant thatexhaust temperature is very sensitive to the richness of the mixture andthat a correct mixture has a characteristic exhaust temperature for anygiven engine. The invention involves the control of air in response toexhaust temperature.

Thus the output of the engine is controlled by controlling the fuel andthe appropriate quantity of air is controlled by exhaust temperature. Agovernor responsive to load, for example a speed responsive governor,may be used to vary fuel quantity, and the thermal control independentlycorrects the air quantity in response to exhaust temperature changesresulting from too much or too little air. The temperature responsivecontrol can be made suiciently sensitive to assure satisfactoryoperation of the engine over a wide range of load.

Cil

piston l. The controlling and operating mechanism for the fuel inletvalve 5 is not illustrated. as it might be any device known in the art.Control by a governor would be the usual arrangement. The cylinder l isprovided with a head I having a water jacket 8. The ignition sparkplugis mounted in the head and is indicated at 9. The cylinder is shownmounted in a crankcase indicated at li. "'There is the usual crank I2and connectingrod` I3.

A scavenging air blower il of ordinary form is driven by any means knownin the art. The

. drive for the blower Il is conventional and is The invention isdirected broadly to this concept. It will be described as applied to anengine of the port scavenged type, using combustible gas as fuel, andmaking use of spark ignition. This particular type oi.' engine isselected because of its simplicity, and as a basis for disclosing theinventive concept. The invention is not limited to any specific type ofengine but might be applied to any two cycle internal combustion engineto which scavenging air is supplied under pressure.

The single gure of the drawing illustrates an engine of the type justmentioned, chieiiy in vertical section. with the invention applied. Thethermostatic device is shown in diagram.

In the drawing the engine cylinder is indicated at l. scavenging ports3. The cylinder is water-jacketed as indicated at 4 and has a fuelinjecting valve 5 located at a point overtraveled by the This cylinderhas exhaust ports 2 and not illustrated. It is common in the art. forexample, to drive the blower by an electric motor. or to connect it tobe driven from the engine crank shaft. The blower delivers scavengingair through pipe I5 to the ports 3. The exhaust port 2 leads to anexhaust pipe Il.

Flow through the scavenging air pipe I5 is regulated by athermostatically controlled valve diagrammatically illustrated at II.The thermally responsive controlling element of the valve Il isindicated at I8 and is located in the exhaust pipe i6 so as to besubject to the temperature of the exhaust gases. The element I8 andvalve i1 are so related that on fall of temperature at Il the valve Ilmoves in its closing direction, and conversely. l

Various actuating connections between a thermostat and a valve are knownin the temperature control art, and any appropriate one may be selected.

The regulation should be such that ii the temperature of the exhaustgases tends to rise above a chosen value the supply of air is increasedand if the temperature falls below such value the supply of air isdiminished. Thus the relationship of air quantity to exhausttemperatureis direct as contradistinguished from inverse. This does not implystrict proportionality, however. As stated, a control of this type canbe made effective to hold the proportions of the fuel and air mixturewithin a range close enough to assure good combustion.

The valve I'I with thermostatic control is selected as probably thesimplest means for vary ing the rate of iiow of scavenging air, but anymeans which would vary the effective output of the blower i4 might besubstituted. In other words, the invention is not directed to anyparticular means of controlling the output of a particular form ofblower. On the contrary, it is based on the concept of controlling theoutput of whatever-means supplies scavenging air to the engine yandcontrolling it in response to the exhaus't; temperatures oi' thatengine.

Various ways of availing of this broad principle will suggest themselvesto persons skilled in the art. and no limitation to the particularconstruction illustrated in the drawing is implied. Moreover, the enginemay be of various different types. It might have various valvearrangements and any known means for ignition.

What is claimed is:

1. The method of relating the supply of combustlon air to variations offuel fed to an internal combustion engine -of the type to whichcombustion air is delivered under pressure to the combustion space,which method comprises sensing the temperature of exhaust gasesdischarging from the engine and varying the rate of combustlon air ilowin a direct relation thereto.

2. The method of relating the supply of combustlon air to variation offuel fed to an internal combustion engine of the type to whichcombustion air is delivered under pressure to the combustlon space.which method comprises sensing the temperature of exhaust gasesdischarging from the engine and variably restricting the flow ofcombustion air in such relation to said temperature that the ow of saidair is increased and decreased as exhaust temperature rises and falls.

3. The method of controlling an internal combustion engine of the typein which fuel is injected into the combustion space and combustion airis delivered under pressure to the combustion space, which comprisescontrolling the output of the engine by varying the quantity of fuel inljected per cycle; and adjusting the quantity of air supplied per cyclein a direct relation to the temperature of exhaust gases from theengine.

4. The method of controlling an internal combustlon engine of the typein which fuel is injected into the combustion space and combustion airis delivered under pressure to the combustion space, which comprisescontrolling the output of the engine by varying the quantity of fuelinjected per cycle according to the load on the engine; and adjustingthe quantity of air supplied per cycle in a direct relation to thetemperature of exhaust gases from the engine.

5. The combination of an internal combustion engine having a variablefuel supply a combustion air passage and an exhaust passage; aircompressing means for supplying scavenging air to the rst named passage;a thermostat in the second named passage; and means actuated by saidthermostat and controlling the rate of supply of air by said aircompressing means in a direct relation to the temperature of exhaustgases ilowing through the second named passage.

6. The combination dened in claim 5 in which the means actuated by thethermostat comprises a valve.

7. The combination of an internal combustion engine having a variablefuel supply a combustion air passage and an exhaust passage; a blowerarranged to deliver air under pressure to the combustion air passage; avalve interposed between the blower and said passage; a thermostatsubject to the temperature of exhaust gases flowing through said exhaustpassage; and an operating connection between said thermostat and saidvalve so arranged that the thermostat moves the valve in an openingdirection in response to rising temperature.

KARL V. ANDERSON.

REFERENCES CITED The following references are oi record in the le ofthis .patentz UNITED STATES PATENTS Number Name Date 1,959,041 SchimanekMay 15, 1934 2,013,998 Goldsboroughv Sept. 10, 1935

